The present invention relates generally to the field of organic semiconductors and, more particularly, to substituted pentacenes that exhibit improved electronic and processing properties as well as electronic devices made with those substituted pentacenes.
Acenes, as a class of graphite substructures, are particularly attractive targets in the synthesis of organic semiconductors because of the predicted low band gap of the polymer. The usefulness of acene oligomers such as pentacenes are already showing in numerous electronics applications including, but not limited to, thin-film transistors (display technologies), solar cells and light-emitting diodes.
Solubilized acenes have received limited attention due to their synthetic inaccessibility. More specifically, while the properties and limitations of simple, linear conjugated organic systems have been well studied by either synthesis or structure-property determinations performed on series of oligomers, few such studies have been performed on fused aromatic systems, simply because of a lack of synthetic methodology available for their preparation. Although a number of researchers have made excellent approaches to planerized graphitic oligomers and polymers, and simple fused aromatic systems based on the graphite lattice are already being explored for the construction of field effect transistors (FETs) and molecular electronic devices, the lack of a reliable route to synthetically-tailored linearly fused aromatics has precluded the development of fully tunable organic materials.
The ability to tailor organic materials to maximize film-forming abilities or solid-state order cannot be understated, as such customization will allow the use of such systems as components for EMI shielding or corrosion-resistant coatings and as electrodes for flexible flat-panel displays or solar panels. The charge-storing ability of the aromatic polymers also has application in the fabrication of lightweight, moldable organic batteries. Functionalization will also allow us to explore self-organization in these graphite-like systems. Pendent groups on an oligoacene can be used to alter the solid-state ordering of the material.
The present invention relates to substituted pentacenes that have been, functionalized with pendent groups tailored to influence the processability, solid-state order and stability of the resulting material. Advantageously, the substituted pentacenes of the present invention may be prepared on a large scale at a low cost: necessary characteristics for eventual commercial applications. Additionally, the substituted pentacenes have significantly improved electronic properties when compared to pure pentacene materials.
The present invention relates to novel substituted pentacene compounds comprising the formula: 
wherein R1=a branched or unbranched alkane having C2-18, a branched or unbranched alkyl alcohol having C1-C18, a branched or unbranched alkene having C2-18, an aryl or heteroaryl (e.g. thiophene, pyridine) having C4-18, an alkylaryl or alkyl-heteroaryl having C5-32, a ferrocenyl or SiR2 where R2=hydrogen, a branched or unbranched alkane having C1-10, a branched or unbranched alkyl alcohol having C1-C10, or a branched or unbranched alkene having C2-10.
In accordance with yet another aspect of the present invention an electronic film is constructed from the novel substituted pentacene compounds of the present invention. Still further a transistor and photovoltaic device including one or more of the novel compounds of the present invention are also provided.